On the one hand... Carlos Santana is wrapping up his best month of the season.
Santana entered July with a .213/.350/.369 batting line that gave him a wRC+ of 108, which was one point better than the collective wRC+ of all American League first basemen, but not anywhere near what Carlos put up in each of the last couple seasons. In July, Santana has hit .267/.375/.453, with a wRC+ of 135. His isolated power (ISO = slugging percentage - batting average) for the month is .187, which is only a touch below his ISO during the previous two seasons, which was .192. Santana has been just as good at the plate this month as he was during 2013 and 2014 A hair better, in fact), when he was one of the 20 to 25 best hitters in baseball.
It should be noted that Santana's .321 BABIP in July is not sustainable for him, but then neither was the .221 BABIP he had in May and June. In a fun twist, his career BABIP exactly splits the difference between those two, coming in at .271.
Add in his 3 for 3 base stealing and some other nice base running, and even with below average defense as a relatively easy position, and Santana has been worth 0.7 fWAR in 23 games during July, which projects out to 4.5 fWAR for 150 games.
On the other hand... Carlos Santana is still in the midst of the worst season of his career.
Santana's batting line for the full season is .225/.355/.389, which gives him a wRC+ of 114. Most fans would reject the notion that Santana has been a better hitter than the average first baseman, because most fans still can't see past a .225 batting average. Even Santana's biggest supporters (I think it's safe to say I'm near the top of that list; between posts, comments, and tweets, it is entirely possible that I have written more words in support/defense of Santana over the last three years than any other person on the planet... seriously.) have to acknowledge that "better hitter than the average first baseman" is not the bar we want Santana clearing, and this has not been a good season for him.
What's been different?
The biggest change in Santana's game from last season to this one is the decline in his power. Santana hit 27 home runs in 2014, leading the team for the third time in four years. This season he has 11, putting him on pace for 18. He's hitting more doubles than he did a year ago, but doubles aren't as good as home runs. Santana's ISO last year was .196; this year it is .164.
Santana's batted ball rates have changed:
- ground ball: 40.1% in 2014; 45.7% in 2015
- line drive: 19.5% in 2014; 16.8% in 2015
- fly ball: 40.4% in 2014; 37.5% in 2015
Fewer balls in the air means fewer home runs, especially when a lower percentage of your fly balls (11.5% this season) are going over the fence than they were a year ago (16.1% in 2014).
Why won't Santana attack the shift by hitting to the opposite field?
I don't know, but I'm not sure I really buy the argument that this is what's holding him back.
Santana's pull rate in 2014 was 60.5%, the highest of his career and the highest of any MLB player for a full season this decade. This season, his pull rate is 49.2%. That's still very high, of course, but my point is he's not pulling the ball nearly as much as he did last year. He's hitting it to center field a lot more often and going to the opposite field a little more often too.
That he won't just "change his approach" may explain why he isn't the type of hitter you want him to be, it doesn't seem to explain why he isn't a better hitter this season. I suspect changing one's approach isn't as easy as many fans would have you believe, especially if you don't want to lose the good with the bad. Maybe Santana has tried to go the opposite way more often, and maybe that's why his power is down. I'm not saying that is the case, but it's at least as logical as thinking Santana could simply go the other way whenever he wants to and still have plus power the rest of the time. Baseball is a lot harder than that.
Perhaps pitchers have identified his weaknesses and are pitching him differently.
Perhaps, but if so, the changes they've made don't seem to be showing up in the numbers. A common complaint is that Santana can't hit off-speed pitches well, but it turns out pitchers have been throwing him slightly fewer of those this season than in years past. He's seen 54.8% fastballs this season, the highest percentage of his career. Santana has actually had more success on off-speed pitches this season than last, it's against the fastball that his production has dipped.
Pitchers also aren't throwing him any more balls or strikes than usual. The theory that pitchers know he'll just take good pitches, and are now throwing more of them isn't supported by the facts. His career zone rate (percentage of pitches inside the zone) is 43.5%. This season it's 43.2%.
Santana isn't chasing pitches outside the zone more than in years past either. His O-swing% is 21.9% this year, basically identical to his 22.0% figure from last year and down slightly from his 22.5% career rate. He's making less contact on pitches outside the zone, and more contact on pitches inside the zone.
So what is it then?
Again, I don't know. I would love to be able to come to you saying "Santana has been really good this month, and here is the explanation for what was going wrong before that this season." None of my research was able to tell me that.
My research did tell me that the common refrains about pitchers attacking him differently and Santana being unable to adjust and go to the opposite field this season don't seem to explain he difference between this year and last.
Pitchers aren't attacking him in the zone more often, and they aren't throwing off-speed pitches more often. Santana isn't swinging at more pitches outside the zone, and he isn't pulling the ball more.
If I had to bet, I'd put my money on Santana's August and September being better than the first half of his season, but not as good as his July. He'll finish the year as an above average player, but one who continues to frustrate a huge segment of his team's fan base.